Linux Fu: Docking Made Easy

June 21, 2022 by 20 Comments

Most computer operating systems suffer from some version of “DLL hell” — a decidedly Windows term, but the concept applies across the board. Consider doing embedded development which usually takes a few specialized tools. You write your embedded system code, ship it off, and forget about it for a few years. Then, the end-user wants a change. Too bad the compiler you used requires some library that has changed so it no longer works. Oh, and the device programmer needs an older version of the USB library. The Python build tools use Python 2 but your system has moved on. If the tools you need aren’t on the computer anymore, you may have trouble finding the install media and getting it to work. Worse still if you don’t even have the right kind of computer for it anymore.

One way to address this is to encapsulate all of your development projects in a virtual machine. Then you can save the virtual machine and it includes an operating system, all the right libraries, and basically is a snapshot of how the project was that you can reconstitute at any time and on nearly any computer.

In theory, that’s great, but it is a lot of work and a lot of storage. You need to install an operating system and all the tools. Sure, you can get an appliance image, but if you work on many projects, you will have a bunch of copies of the very same thing cluttering things up. You’ll also need to keep all those copies up-to-date if you need to update things which — granted — is sort of what you are probably trying to avoid, but sometimes you must.

Docker is a bit lighter weight than a virtual machine. You still run your system’s normal kernel, but essentially you can have a virtual environment running in an instant on top of that kernel. What’s more, Docker only stores the differences between things. So if you have ten copies of an operating system, you’ll only store it once plus small differences for each instance.

The downside is that it is a bit tough to configure. You need to map storage and set up networking, among other things. I recently ran into a project called Dock that tries to make the common cases easier so you can quickly just spin up a docker instance to do some work without any real configuration. I made a few minor changes to it and forked the project, but, for now, the origin has synced up with my fork so you can stick with the original link.

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Up In The Sky… It’s A Bird… It’s A Drone… Oh Yeah, It’s A Drone

June 21, 2022 by 15 Comments

One staple of science fiction is the ornithopter, which is a plane with moving wings. While these haven’t proved very practical in the general sense, a recent paper talks about mimicking natural wings changing shape to improve maneuverability in drones and other aircraft. In particular, the paper talks about how the flight performance of many birds and bats far exceeds that of conventional aircraft.

The technical term for being more maneuverable than a conventional aircraft is, unsurprisingly, called supermaneuverability. Aircraft performing things like the Pugachev Cobra maneuver (watch the video below, or the latest Top Gun movie) require this type of operation, and with modern aircraft, this means using thrust-vector technology along with unstable airframes and sophisticated computer control. That’s not how birds or bats operate, though, and the paper uses modern flight simulation techniques to show that biomimicry and thrust vector technology don’t have to be mutually exclusive.

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No Tool Left Behind With The Help Of Homemade Shadow Boards

June 21, 2022 by 38 Comments

Shadowed tool storage — where a tool outline shows at a glance what’s missing from storage — is a really smart way to keep your shop neat. They’re also super important for cases where a tool left behind could be a tragedy. Think, where’s-that-10-mm-socket-while-working-on-a-jet-engine? important. (It’s always the 10-mm socket.)

But just because shadow boards are smart, doesn’t mean they’re easy to make. That’s why [Scott Prince] came up with this semi-automated method for making toolbox shadow boards. The job of tracing around each tool on some sort of suitable material and cutting out the shapes seems straightforward, but the trick comes in organizing the outlines given the space available and the particular collection of tools.

[Scott]’s method starts with capturing images of each individual tool. He used a PiCam and a lightbox housed, strangely enough, in a storage bench; we’d love to hear the full story behind that, but pretty much any digital camera would do for the job. After compensating for distortion with OpenCV, cropping the images, and turning the image into a vector outline of the tool, [Scott] was left with the task of putting the tools into logical groups and laying them out sensibly. After tweaking the tool outlines and adding finger cutouts for easy pickup, [Scott] put his CNC router to work. He chose to use a high-density polyethylene product made by his employer, which looks fantastic, but MDF would work fine too.

We have to admit to a fair degree of toolbox envy now that we’ve seen what shadow boards can do. We’re a bit torn, though — [Zach Friedman]’s Gridfinity storage system has a lot going for it, too.

Wonderful Foldable Printable Dodecahedron

June 20, 2022 by 14 Comments

Debra Ansell of [GeekMomProjects] fame came up with a neat, 3D design that prints flat and then folds up into everyone’s favorite Platonic solid: a D12.

Why would you want to do this? Well, folding up your 3D prints gives you a third dimension “for free” without using all that support material. Here, all of the outside faces of the dodecahedron are printed flat against the build plate, which is probably the nicest side of your prints. And embedding LEDs in the resulting shape would probably be easy because they’re all in plane. And speaking of LEDs, we kinda expected to see them here, given Debra’s motto: “LEDs improve everything” — that part is up to you.

Debra notes that she likes PETG instead of PLA for the extra strength in the thin-printed hinges, and we’d bet that your printer’s tolerances will need to be spot on for the clips that hold the whole thing together. (We’d be tempted to apply a little super-duper glue.)

As always with Debra’s projects, there’s some creative solutions on display here that’ll help you out whether you need a D12 or a D20, so give it a look!

Thanks [Peter] for the tip.

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Blinking An Arduino LED, In Julia

June 20, 2022 by 11 Comments

The Julia programming language is a horrible fit for a no-frills microcontroller like the ATMega328p that lies within the classic Arduino, but that didn’t stop [Sukera] from trying, and succeeding.

All of the features that make Julia a cool programming language for your big computer make it an awful choice for the Arduino. It’s designed for interactivity, is dynamically typed, and leans heavily on its garbage collection; each of these features alone would tax the Mega to the breaking point. But in its favor, it is a compiled language that is based on LLVM, and LLVM has an AVR backend for C. Should just be a simple matter of stubbing out some of the overhead, recompiling LLVM to add an AVR target for Julia, and then fixing up all the other loose ends, right?

Well, it turns out it almost was. Leaning heavily on the flexibility of LLVM, [Sukera] manages to turn off all the language features that aren’t needed, and after some small hurdles like the usual problems with volatile and atomic variables, manages to blink an LED slowly. Huzzah. We love [Sukera’s] wry “Now THAT is what I call two days well spent!” after it’s all done, but seriously, this is the first time we’ve every seen even super-rudimentary Julia code running on an 8-bit microcontroller, so there are definitely some kudos due here.

By the time that Julia is wedged into the AVR, a lot of what makes it appealing on the big computers is missing on the micro, so we don’t really see people picking it over straight C, which has a much more developed ecosystem. But still, it’s great to see what it takes to get a language designed around a runtime and garbage collection up and running on our favorite mini micro.

Thanks [Joel] for the tip!

3D Printed Concrete Beam Improves Sustainability

June 20, 2022 by 38 Comments

Many of the 3D printed houses and structures we’ve seen use concrete and are — frankly — a little underwhelming. Making big squares out of concrete isn’t that hard and while we are sure there is some benefit, it isn’t overwhelming. [Andy Coward] apparently felt the same way and set out to find ways that 3D printing could offer unique benefits in building structures. The result: a beam that would be difficult to create with conventional techniques but is easy to make with a printer. The advantage is that it uses 78% less concrete than a conventional beam with the same properties.

The key is that in a normal beam, not much of the concrete is bearing a significant load. It is simply there because you need some concrete on one side of the beam and then some more on the other side. In the center, surprisingly little of the concrete actually supports anything. The new beam takes advantage of this along with a steel reinforcement at a strategic point. Still, it uses 70% less steel than a typical reinforced beam.

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Don’t Mind If I Ski-Do

June 20, 2022 by 6 Comments

There is an age-old tradition among hackers of just making it yourself. Whether the real thing is too expensive or you think you can make a better one, the itch strikes, and it can quickly spread. [Homemade Madness] has quite the itch as he builds his own jetski.

What is a jetski but a boat with a shell on top? In an earlier video, he created a boat out of plywood and, after the usual steps of fiberglass and sealing, was proud to float around in his relatively normal-looking boat. But now that he had a working bottom, it was time to return to CAD. He printed out templates for all various shapes he would need, each labeled with a different designator, and glued them to the plywood. No fancy CNC here, just a steady hand and a jigsaw. We love the professional build instructions he compiled for himself that detail in LEGO-like quality exactly how each piece slots into where and in what order to do them. In addition to the top layer of the jetski, he also designed a stand for the boat to rest on while he made it, which is just going the extra mile. A ceiling-mounted winch made it easy to lift the ship into position. Next, he connected all the various framing pieces with PU glue. Thin plywood acted as cladding on top of the skeleton. Filling, sanding, and fiberglass overlaid the structure, making it waterproof. More sanding and some primer later, and it was ready for another water test.

He designed a version with an outboard motor, but he’s trying to build one with a built-in jet drive. So we’re looking forward to seeing the next step and him flying around on his custom watercraft. But what he has already done is quite impressive. If you’re looking for something a little smaller to pull you around the water, why not take a look at this little 3d printed tug boat? Video after the break.

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